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,(. . C --f.J7.J. Jel7 C "::i)L< D'[i!~m5fWl d M.q;' 11 /924 - COLORA CO!\lSERI/^!!O WArER "'I/DA'Rt:tA;"_ COLORADO RIVER above CISCO, UTAH: The water supply outlook calls for more~J adequate supplies with high water e~~ected in most areas and some flooding in low lying areas. Areas experiencing high water conditions last year are likely to get a repeae again this year. WATER SUPPLY OUTLOOK FOR COLORADO 00 un as of May 1, 1984 Stearnflow forecasts jumped 15 to 20% over most of the basin as late April snow- storms dumped copious amounts thro~ghout the upper Colorado. The most significant increases were in the southwest area of the basin where increases were 25 to 40% over last months forecast. FOl"e(;dsts for slluwmel t rW1ofi' range from 144% i!l the headwaters of the GUImisGD basin to over 200% on the lower ~rrillison drainage, San Miguel River and the Colorado mainstem at Cisco. April precipitation was heavy alcng the continental divide and in northwest Colorado where amounts were generally 140 to 180% of average. The only area to receive less than average was over the central Gunnison basin where monthly totals were 85 to 100% of normal. Seasonal precipitation accumulations, October through April, are generally 120 to 170% over most of the basin. Some records or near records include: Grand Junction 7.40 inches, 159% - wettest since 1941; Grand Lake 6SSW 9.36 inches, 150% - wettest since 1952; Green Mountain Dam 12.76 inches, 157% - wettest on reccrd eating back to 1940; Ouray 21.78 inches, 170% - wettest on record datir~ back to 1936; and Shoshone 18.30 inches, 148% exceeded only once in the last 50 years. The cool, wet April continued to add to the snowpack, with May 1 snow surveys showing significant increases, quite similar to lase y~ar. SOfie average basin snow water contents include: Upper Colorado - 169%, upper Gunnison - 156%, Roaring Fork - 164%, Dolores - 176%, and cncornpahgre - 183%. The May 1 surveys also indicated that 44 new ~~y 1 reccrds were established, many in the upper Colorado and Gunnison drainages, some datin~ back ~o the late 1930's. Runoff during April was near normal to slightly below in the headwater areas but increased significantly in the lower basins with the onset of the low elevation snowmelt. The flow on the Colorado River at Cisco, Utah was 695,200 acre-feet, 170% of normal. The total flow since October 1 has been 2.4 milli~n a~re-feet, 152% of the 20-year (1961-1980) normal, exceeded only twice in the last 60 years, 1942 and 1962. Seasonal inflow to L~ke Powell has been 5.3 million acre-feet, 150% of normal. Reservoir storage as of May 1 in the four major reservoirs above Cisco, Utah (Lake Granby, Dillon, Green Mountain and Blue Mesa) is 826,500 acre-feet, nearly 200,000 acre-feet lower than laSe year at this time, 102% of average and 49% of capacity. Storage in Lake Powell is 21.06 million acre-feet, 84% of capacity and 1.7 million acre-feet lower than last year at this time. The April-July inflow forecast to Lake Powell is 13.0 million acre-feet, 174% of the 20-year (1961-1980) average. NOAA-NATIONAL 'NEATHER SERVICE COLORADO BASIN RIVER FORECAST CENTER SALT LAKE CITY, UTAH Gerald Williams, HYdrologist-in-Char~e